Interpretation ID: nht95-3.21

TYPE: INTERPRETATION-NHTSA

DATE: June 19, 1995

FROM: Patrick M. Raher -- Hogan & Hartson

TO: John Womack -- Acting Chief Counsel, NHTSA

TITLE: Re: Request For Interpretation - Seat Positioning Procedure Under FMVSS 208, 214

ATTACHMT: ATTACHED TO 8/31/95 LETTER FROM JOHN WOMACK TO PATRICK M. RAHER (A43; STD. 208)

TEXT: Dear Mr. Womack:

In the process of reviewing the requirements contained in the seat positioning procedures of FMVSS 208 and 214 for purposes of providing guidance to one of our clients, we noted that, depending on the interpretation of certain provisions, there is a p otential for as many as three different seating positions that could occur in a dynamic test. Such a situation is unacceptable from a certification and compliance standpoint. Accordingly, we are requesting an interpretation from your office.

FMVSS 208 (S8.1.2) and 214 (S 6.3) specify that "adjustable seats are in the adjustment position midway between the forward most and rear most positions, and if separately adjustable in the vertical direction, are at the lowest position." We have inte rpreted the foregoing to require that the midway point between a seat's maximum forward and maximum rearward position is the point at which the seat in its lowest configuration must be placed for purposes of testing. A question has arisen, however, with respect to power seats which have different maximum seating locations in the forward and rearward position depending on seat height. In such a situation the language of both standards could be interpreted to allow positioning of the seat at other than the true mid-point.

In order to provide you with an indication of the basis for this issue arising, we are enclosing three diagrams indicating driver seat ranges of motion for a power seat type assembly. These diagrams include step-by-step instructions on three possible interpretations of seat positions for adjustable seats prior to dynamic crash testing. We believe that since the seat positions described in all three operations vary because the seat position potential is trapezoidal rather than rectangular, due to th e mechanism utilized in the power seat operation, there are potentially different interpretations of the standards and, therefore, it is appropriate for your office to issue an interpretation clarifying this matter.

The impact of the three options is relatively clear. For example, when option 1 in the attachment is followed, the midway position of the seat is determined by

* raising the seat to its highest position and moving it forward, which is the farthest forward position;

* lowering the seat and moving it to its furthest rearward position; * finding the midway point of these two positions;

* moving the seat to midway position identified by the foregoing calculation

As you can see from Option 2 in the attachment, it is also possible to read the regulation to allow for the same forward and rearward reference points but to move the seat in its upward position to the mid-point and then lower the seat which, because of its mechanical operations, would actually move the seat back from the true midpoint of the seat travel line. Finally, Option 3 in the attachment could lead to a situation where the lowest seat position is used for identifying the forward and rearward most locations and identifying a midpoint. This, we believe is the most unlikely of all three interpretations because it fully ignores the most forward seating position.

In view of the importance of this interpretation to the issuance of proper legal advice under your regulations, we would very much appreciate a prompt interpretation of this question. We are, of course, fully prepared to meet with you or discuss the situation by telephone, to clarify any questions you may have and expedite issuance of a response to this request. We look forward to hearing from the Agency with respect to their interpretation of this matter.

Best regards.